Process for introducing an aldehydic group into heterocyclic nitrogen compounds



Patented June 10, 1930 UNITED STATES PATENT orrlce GEORG KALISCHER AND HEINZ SOHEYER, FRANKFOBT-ON-THE-MAIN, AND KARL KELLER, OF MAINKUR, NEAR FRANKFURT-ON-THE-MAIN, GERMANY, ASSIGNORS TO GENERAL ANILINE WORKS, INC, 01 NEW YORK, N. Y., A CORPORATION OF DELAWARE PROCESS FOR INTRODUCING AN ALDEHYDIC GROUP INTO HETEBOGYCLIC NITROGEN COMPOUNDS No Drawing. Application filed January 30, 1928, Serial No. 250,719, and in Germany February 2, 1927.

all necessary for the process and that the reaction takes place when using heterocyclic compounds, in the molecule of which no aminogroups but nitrogen in ring binding is present.

5 Our process consists in acting on such heterocyclic nitrogen compounds in presence of a condensation agent containing chlorine with a formyl-amino compound of the general formula an wherein X and X represent hydrogen or aryl, or X represents aryl and X represents alkyl. As heterocyclic nitrogen compounds not containing an aminogroup, which are suitable for our process may be named pyridine, quinoline, carbazol, N-alkyl derivatives of carbazol and naphthostyril.

The aldehydic derivatives thereof, are mostly obtainable according to our process with an excellent yield and in a very pure state. They are important intermediates for the production of dyestuffs.

5 In order to further illustrate our invention the following examples are given, the parts being by weight and all temperatures in centigrade degrees. But we wish. it to be understood that we are not limited to the particular conditions nor to the specific products mentioned therein.

Example 1 9,7 parts of N-ethylcarbazol are introduced without cooling into a mixture of 13,5 parts of formylmonomethylaniline and 15,3 arts of phosphorus oxychloride. The liquor turns to a reddish color and warms to about 80 with an evolution of hydrochloric acid.

For finishing the reaction the mass is warmed for a short time on the waterbath. Then it is poured on water and the product of reaction, whlch separates first in an oily state, solidifies to a granular yellow precipitate. The new aldehydic compound thus obtained corresponds probably to the formula:

CelLvCaHr-CHO When recrystallized from the usual organic solvents, e. g. from alcohol it forms yellow- 1sh crystals melting at about 87. It dissolves in sulfuric acid with an orange-yellow color. Its aldazine represents yellow needlessoluble in sulfuric acid with a bluish red color.

The probable course of the reaction may be Illustrated by the following hypothetical equations:

Example 9 Into a benzolic solution of a reaction mixture of 13,5 parts of formylmonomethyL aniline and 15,4 parts of phosphorus oxychlorlde at ordinary temperature 16,9 parts of naphthostyril are introduced, which may be entirely dissolved by gently warming the liquor. After standing for about 24 hours the mass is poured on ice water, then a solution of soda is added until an alkaline reaction and benzene and the formed monomethylaniline is removed by steam distillation. The remaining reaction product may be purified by extracting it with warm alcohol. The new naphthostyrilaldehyde, which seems to correspond to the formula:

0 C=NH is thus obtained as a ellow powder, it crystallizes from monoc orobenzeneas compact yellow risms of about 228 M. P.

- We c aim:

1. Process for introducing an aldehydic groupl into heterocyclic nitrogen com ounds whic process comprises acting on eterocyclic nitrogen compounds in WhlCh no hydrogen atom is substituted by an aminogroup in presence of a condensation agent containing chlorine with a formylamino compound of the general formula X: 11-0 O-N wherein X and X, represent hydrogen or aryl, or X represents aryl and X, represents alkyl.

2. As a new compound the N-ethylcarbazolaldehyde, corresponding probably to the formula:

representing yellowish crystals of about 87 melting point, when recrystallized from the usual organic solvents, soluble in sulfuric acid with an orange-yellow color, forming 36 an aldazine, which crystallizes as yellow needles and is soluble in sulfuric acid with a bluish red color.

In testimony whereof, we aflix our signatures.

GEORG KALISCHER, HEINZ SCHEYER, KARL KELLER. 

